From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:36039 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727686AbeJNXLy (ORCPT ); Sun, 14 Oct 2018 19:11:54 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Michael Ellerman" , "Nicholas Piggin" Date: Sun, 14 Oct 2018 16:25:41 +0100 Message-ID: Subject: [PATCH 3.16 330/366] powerpc/powernv: Fix NVRAM sleep in invalid context when crashing In-Reply-To: Sender: stable-owner@vger.kernel.org List-ID: 3.16.60-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Nicholas Piggin commit c1d2a31397ec51f0370f6bd17b19b39152c263cb upstream. Similarly to opal_event_shutdown, opal_nvram_write can be called in the crash path with irqs disabled. Special case the delay to avoid sleeping in invalid context. Fixes: 3b8070335f75 ("powerpc/powernv: Fix OPAL NVRAM driver OPAL_BUSY loops") Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Ben Hutchings --- arch/powerpc/platforms/powernv/opal-nvram.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) --- a/arch/powerpc/platforms/powernv/opal-nvram.c +++ b/arch/powerpc/platforms/powernv/opal-nvram.c @@ -43,6 +43,10 @@ static ssize_t opal_nvram_read(char *buf return count; } +/* + * This can be called in the panic path with interrupts off, so use + * mdelay in that case. + */ static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index) { s64 rc = OPAL_BUSY; @@ -57,10 +61,16 @@ static ssize_t opal_nvram_write(char *bu while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { rc = opal_write_nvram(__pa(buf), count, off); if (rc == OPAL_BUSY_EVENT) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); opal_poll_events(NULL); } else if (rc == OPAL_BUSY) { - msleep(OPAL_BUSY_DELAY_MS); + if (in_interrupt() || irqs_disabled()) + mdelay(OPAL_BUSY_DELAY_MS); + else + msleep(OPAL_BUSY_DELAY_MS); } }